This invention relates generally to turbine engines, and, more specifically, to methods and apparatus for heating a fluid for use in a turbine engine.
In some known gas turbine engines, heat energy from a primary thermal fluid, such as, but not limited to combustion gases and/or exhaust gases, is recovered and used in other engine functions. For example, recovered heat may be used to heat fuel to increase turbine efficiency. Heating a gaseous fuel before combustion removes liquids from the gaseous fuel, which in turn, increases a service life of the engine and increases power output of the turbine. When an oil fuel is used in a turbine, heating the oil fuel before combustion increases the ease of pumping by reducing the viscosity of the oil fuel and facilitates atomization of the oil fuel. Another example of a use for recovered heat is heating inlet air to increases turbine efficiency. Preheating air entering a combustor decreases the amount of fuel needed in the combustor. Additionally, recovered heat systems may be used to prevent ice from forming on the engine.
Some known turbines recover heat by using either a regenerator or a heat exchanger that is built into a Heat Recovery Steam Generator (HRSG). In some known gas turbines, a regenerator is positioned between a compressor and a combustor to heat air entering the combustor. More specifically, to heat the inlet air, turbine exhaust gases flow through the regenerator in an opposite direction to the direction of the flow of the combustor inlet air to heat the inlet air. Other known turbines use an additional heat exchanger in a HRSG to preheat fuel using recovered steam. However, the addition of a regenerator or a heat exchanger may add cost and/or complications to an already complex power generation system. Moreover, the regenerator and/or heat exchanger may occupy a large physical space within a power plant, and/or either component may also require being coupled to a water supply system within the plant.